Systems that transport and process liquids, or slurries containing liquids and solids, or gas streams containing solids are ubiquitous in chemical processing, raw material mining, manufacturing and storage operations. Such process streams may contain one or more components that cause erosion, corrosion, and other changes in the equipment making up such systems. For example, slurries contain particles that may be very abrasive thereby causing erosion as the particles travel through piping, move through tanks, or are otherwise manipulated in the equipment. Various liquids may contain components that react with the metals to cause corrosion of the equipment. Some liquids may cause material loss or damage to the equipment by both corrosion and erosion. In other liquids, scale may undesirably build up in the equipment.
Certain techniques may be employed to identify material loss or other damage. A portion of equipment such as a section of piping could be removed and the interior can be visually inspected or the thickness of the pipe wall could be measured and compared to a previously measured thickness. However, this technique likely requires stopping the use of the equipment, e.g., flow through the piping, which is disruptive of the manufacturing process. Removal of a portion of the equipment such as the piping and/or the measurement technique may require unacceptable, destructive methods.
In another conventional approach, a coupon constructed of a known material is placed into contact with the liquid being transported or processed. In this conventional construction, the coupon may be in the form of a circular section of pipe. After an interval of time, the coupon is removed for inspection to determine whether material loss or damage has occurred. This approach also has disadvantages. For example, installation and removal of the coupon may still require interruption of the manufacturing process depending upon the configuration of the coupon. Installation and removal of the coupon may also affect the accuracy of the testing. The coupon may be damaged by unintended removal of material such as removal of a portion of the coupon or removal of scale, oxides, or other coatings that may have formed. Removing the coupon and exposing it to e.g., air or humid air could also affect accuracy as chemical reactions may occur as a result. Changes in temperature between the coupon in-situ and the coupon removed could also affect the result.
In addition, the accuracy of such coupon testing can be significantly impacted by how the coupon is placed into the liquid flow path. For example, placing the coupon directly into the path of flow may lead to an incorrect, exaggerated measurement. The rate of removal of material from a coupon by e.g., particles from a slurry is known to be highly dependent on the geometry and location of the coupon. Furthermore, the presence of the coupon may interrupt the normal path of fluid and thereby result in measuring inaccurate wear rates.
Accordingly, a device for detecting corrosion or erosion occurring in various equipment including e.g., piping systems would be useful. Such a device that can be used to determine e.g., whether scale or other deposits are building up on the equipment, whether material losses from corrosion or erosion are occurring, estimating the amount of build-up or material losses, and combinations thereof would be particularly helpful.